Some Australian birds make compost heaps.
Apparently I am interested in birds of Australia at the moment. The male Australian brushturkey (no relation to American turkeys) likes to gather large piles of leaves, branches, and dirt, up to 1.5 metres high in some cases. The brushturkey then defends their pile against all comers. The malleefowl, also from Australia, also makes a big pile of organic matter and buries it in sand. Both birds are building compost heaps, and for a very good reason.
You ever stuck your hand into an active compost heap? As the microbes consume the plant matter they warm the compost quite a bit. It can get pretty hot, up to 70°C, but in the case of the bird compost heaps it gets up to around 35°C. The perfect temperature to incubate eggs.
Yup, the brushturkey and malleefowl have built compost heap incubators. They will add more fuel to maintain a constant temperature until the eggs hatch and the baby chicks push their way out of the pile. I am endlessly delighted with the ingenuity of nature.